CORVALLIS, Ore. (AP) -- Oregon State quarterback Sean Mannion is maturing on the job.
Mannion, a redshirt freshman from Pleasanton, Calif., was named Pac-12 offensive player of the week after throwing for 376 yards and four touchdowns in the Beavers' 44-21 win over Washington State on Saturday. Both statistics were career highs and it was the most passing touchdowns the Beavers have had in a game since 2009.
The Beavers (2-5, 2-2 Pac-12) have relied on Mannion's big arm and exceptional poise to drive the offense through a rocky season in which the running game has been unreliable.
At 6-foot-5 and 218 pounds, Mannion is a classic drop-back passer with a notably calm demeanor and highly developed fundamentals, the product of growing up the son of a high school coach.
"In the huddle he is very calm," said senior tight end Joe Halahuni. "He kind of acts like he doesn't know what's going on, although he obviously does. He just acts like there is no pressure on him."
Mannion was highly touted coming out of Foothill High, but even close observers of the Oregon State program were surprised at how fast his time came.
Coach Mike Riley unexpectedly replaced incumbent Ryan Katz, a junior who had started for the entire 2010 season, with Mannion at halftime of the Beavers' season opener against Sacramento State. Katz started the next game, but came out after one series. The job has been Mannion's ever since.
While many were surprised by Riley's apparent quick hook, the process wasn't as abrupt as it appeared. For months, the 11th-year coach had been impressed by the freshman's intelligence, accuracy and poise. While Katz sat out during the spring with an injury, Mannion was making his case every day during drills.
"I saw it happen in spring practice and then again in fall camp," Riley said. "It just looked like, `Hey, we should play this guy.' " Success did not come right away. The Beavers struggled out of the gate, losing their first four games, and Mannion, while continuing to show promise, has struggled at times with decision making, throwing 10 interceptions in seven games.
With the Beavers running game stalled, Riley and offensive coordinator Danny Langsdorf relied more on Mannion's arm to move the offense, causing him to set school records in passes completed (40) and passes attempted (66) in a 27-19 loss to UCLA.
Through the good and the bad, Mannion has been a steady presence in the huddle, and he has improved from week to week.
"He's become more of a leader every week," Halahuni said. "I see it, after the play he comes on the sidelines and talks about what's going on and what they're going to change."
Mannion is on track to finish the season with 3,367 yards passing, which would be the third-highest total for a single season in school history behind Derek Anderson's 4,058 in 2003 and 3,615 in 2004. The Beavers are currently 18th in the country in passing offense at 297 yards per game.
Off the field, Mannion is cheerful but unassuming. And his elusiveness on the field is also manifested in front of the microphone, where he has already developed a reputation as a guy who can meet the most penetrating question with a polite but unrevealing answer. He rarely answers questions about himself, instead talking about the team or his teammates.
Mannion hesitates to call himself a leader and says he is just trying to play his role as a quarterback.
"I just try to go out every day and get better at practice," he said, "and I hope that that rubs off on other guys."